The invention relates to an apparatus for applying a lining of refractory material, cement, heat insulating material and other insulating materials over the refractory layers of a converter or a furnace including an electric furnace and an open-hearth furnace or a vessel with a great reliability.
In conventional lining operations, the lining material is produced away from the lining operation site and then is transferred to the operation site by means of a long compression supply tube wherein the long floor-laid tube hampers the movement of the lining device when it must move from one converter to another, resulting in an inefficient lining operation.
Furthermore, since the water storage tank, refractory material tank, compressor and the like which are required in the lining operation occupy a large floor area, the operation cannot be conducted efficiently or with adequate mobility.
In addition, these devices are installed apart from each other so that a central control system for the spraying apparatus is hard to achieve. Therefore, at least several workers are required to operate the apparatus.
Meanwhile, in the lining operation, the lining apparatus is moved to a position adjacent to the upper open end of the furnace. Subsequently, the long shooting pipe is extended into the furnace and then the spray nozzle attached to the extremity of the shooting pipe is directed toward the abraded or eroded portion of the furnace lining and the desired amount of refractory material is sprayed onto the above portion so as to repair the lining of a furnace.
In this case, the operator controls the shooting pipe while observing the movement thereof.
However, the mere manipulation of the shooting pipe cannot cover some of the abraded portions on the furnace lining because they are not within the sprayable range of the shooting pipe.
For example, when the spray nozzle is directed from one abraded portion to another, in some cases, the shooting pipe will come into contact with the upper periphery of the furnace if the lining apparatus is kept in the same position. In these cases, the apparatus as a whole must be moved a certain distance to prevent breaking the shooting pipe. The operation to move the apparatus conventionally requires the operator to get off the apparatus or shift his position on the apparatus thereby making the operation very cumbersome.
The applicant of this application has previously disclosed a lining apparatus which can resolve the aforementioned problems in U.S. Pat. No. 3,827,633 (registered on Aug. 6, 1974).
However, the above lining apparatus is less than optimal in view of the following aspects.
(1) In the lining operation by the conventional apparatuses including the above improved apparatus, the refractory material in wet slurry form, which is produced by mixing the powder-like refractory material and water in a desired mixing must be sprayed onto the furnace lining from the spray nozzle.
Especially when applying refractory material while the furnace is still hot, the spraying causes a fall in the temperature within the furnace.
Therefore, the amount of water to be mixed with the powder-like refractory material must take into account the furnace temperature, since the adhering force (adhesiveness) and rebound loss of the sprayed refractory material are greatly affected by the water percentage in the slurry-like refractory material and the temperature in the furnace.
Conventionally, adjusting the water to be mixed is done by throttling a manual valve disposed at the middle of the water supplying tube. Manual operation, however, cannot achieve fine adjustment of the water addition since it depends mainly on the experience of a skilled operator. Furthermore, due to the nature of the spraying operation, the manual throttling is subject to high radiation heat temperature from the furnace.
(2) In the water-cooled construction provided in the conventional spray apparatus, a shooting pipe has a concentric dual pipe construction where the inside pipe thereof passes the refractory material therethrough. Furthermore, the space between the inside pipe and the outside pipe is divided into two or more sections by means of partitions. These sections are used as a feeding and returning way for cooling water. In addition to the above-mentioned water-cooled construction, a guide, or a key and a keyway are required as a mechanism to rotate the shooting pipe about its axis and to move it along its axis. For that purpose, it is difficult from the view point of machining to divide the space between the concentric pipes into two or more sections by means of partitions, which entails a number of processing stages. Furthermore, because a guide or a key and a keyway, which allow the shooting pipe to rotate or move must be separately manufactured, the manufacturing of said pipe becomes more complicated.
Accordingly, it is an object of the present invention to provide an apparatus for applying a refractory lining onto the inner surface of a furnace which can resolve the above-mentioned defects while keeping the advantages of the improved type of apparatus devised by the applicant of this invention.
It is an another object of the present invention to provide such lining apparatus which is provided with a water-regulating system which can finely and accurately regulate the amount of water to be added into the powder-like refractory material.
It is still another object of the present invention to provide such lining apparatus which can automatically cool the shooting pipe during the spraying operation.
It is a further object of the present invention to provide such lining apparatus which is provided with a central control system such that an operator can manipulate all the devices mounted on the transport car easily and precisely while sitting on the seat mounted on the apparatus throughout the spraying operation.
It is still further object of the present invention to provide such lining apparatus which is provided with many other constructional improvements which enhances the mobility and operability of the apparatus such as the means which oscillate the rotation of the shooting pipe.